Previous studies have established the requirement for glucan synthesis from sucrose by glucosyltransferase on the surface of S. mutans to achieve in vitro adherence. Future studies will concern the nature of the surface of the S. mutans cell in relation to the function of the type specific polysaccharide and glucan as binding sites for glucosyltransferase. Con A and other lectins will be employed in these studied. Efforts will also be made to further purify and chemically characterize the bacteriocin receptor sites on the surface of S. pyogenes and other streptococci. A common chemical component is shared by both sensitive and resistant strains. The binding of the bacteriocin and other data suggest the presence of immunity proteins. These studies relate to establishment of S. mutans in the oral cavity.